Move Boolalg to its own submodule

[carlos-adir]

Currently we use boolalg file to simplify boolean expressions. As example a | (~a) -> 1

This is currently inside the shapepy.bool2d, but it should gain its own submodule since the simplification of boolean expressions doesn't need to know the SubSetR2 classes.

[carlos-adir]

Solved by #90